The present invention relates to pens as employed in X, Y graphic plotters, or the like, and more particularly, to capping mechanisms for selectively sealing and unsealing the tips of the pens for writing purposes.
X, Y plotting mechanisms that are used in some applications, such as engineering drawing production, require the use of pens with liquid ink. Between periods of use, such pens must have the writing tips thereof sealed or the ink adjacent the tip will dry out causing skips in the lines being drawn upon initial startup of a line from a pen which has been unused for a period of time, or, in the extreme, complete lack of ink flow from the pen. In the past, prior art plotters employing such pens have employed complex sealing mechanisms for each pen on an individual basis. Thus, for example, in a four pen plotter there would be four sealing members, four actuating bars connected to the four sealing members, and a complex mechanism for selectively recapping one pen while uncapping another. Such complex mechanisms typically add greatly to the cost of the device while simultaneously increasing the probability and possibility of failure with associated downtime of the entire plotter.
Also, the prior art systems are dedicated to a fixed pen configuration and are not easily adapted to new configurations, in particular, to mixing pens requiring sealing and those which are not sealed, such as ball point and felt tipped.
Wherefore it is the object of the present invention to provide a capping mechanism for multi-pen plotters and the like which is simple, of low cost, and reliable and which provides for easy configuration changeability.